The death of PAP Assembly Member Baharuddin Mohammed Ariff precipitated this by-election. Former Chief Minister David Marshall, now WP chief, won the seat, marking WP's debut in the legislature. Meanwhile, independent AM Ong Eng Guan mustered his two former PAP colleagues who resigned with him to form UPP. On 20 July 1961, Prime Minister Lee Kuan Yew tabled a motion of confidence on the PAP government and survived by one vote of 26 to 25 after Siglap AM Sahorat Ahmat, who was in hospital, was wheeled in to vote. The 13 PAP AMs, representing Bras Basah, Queenstown, Chua Chu Kang, Havelock, Jalan Kayu, Moulmein, Nee Soon, Pasir Panjang, Serangoon Gardens, Stamford, Thomson, Toa Payoh and Upper Serangoon, were expelled from the party for voting against the motion.

Writ of election: 23 May 1961 [Tue]
Nomination day: 10 June 1961 [Sat]
Polling day: 15 July 1961 [Sat]
Member swearing-in: 20 July 1961 [Thu]

Eligible voters: 9,816
Voter turnout: 9,566 (97.5%)

Election deposit: $500


General Election 1959
Previous: By-Election April 1961
General Election 1963
Next: By-Election 1965